Effects of agricultural water supply constraints on cropping pattern in Chenaran County (Application of fuzzy multi-objective programming with nonlinear membership function)

Given that farmers try to optimize their individual utility, they generally have different goals, most of which are economic. They usually do not pay much attention to the goals of minimizing water consumption. This study attempted to investigate the addition of water minimizing goal and setting restrictions on the supply of water to the multiple objectives of farmers. It also deals with the impact of this practice on cropping patterns, water use and gross income of farmers. To achieve this, a fuzzy multi-objective programming with nonlinear membership function (hyperbolic tangent) was used. The data was collected out of questionnaires filed by 130 farmers of Chenaran (Khorasan Razavi province) using the random cluster sampling in 2012-2013 crop year. The farmers were divided into three homogenous groups, based on the cultivation area: less than 8 hectares, from 8 to 24 hectares and more than 24 hectares. Then model optimized for each of the three groups was based on the goals of profit maximization, minimization of capital and maximization of labor. Then by adding water minimization to the objectives, effects of these changes were evaluated. The results showed that by entering the water to the objectives of farmers in groups 1 and 3, water consumption was reduced. However, it did not change in Group 2. Also in all 3 groups, onions and cucumber cultivated area was decreased. In contrast, the area under wheat cultivation increased, although this would reduce the income of farmers in all 3 groups. The results also showed that with policy of restrictions on water supply in addition to changing cropping patterns and decrease in income, the total cultivated area will decrease in all 3 groups.